To give you an idea about "polynomial spread" of the Holy Channel: In the picture you'll see the 2 sigma standard deviations for all the polynomial degrees from 1 to 8 plus the respective ranges in pips. Which level is the right one? I don't know - they change with every bar, that's what regressions do. However, they give a statistics based perspective of market structure rather than a discretionary one. And yet, must you decide when to pull the trigger.